水岩作用下红层软岩损伤劣化特征及本构模型研究  

Damage and deterioration characteristics and constitutive model of red layer soft rock under the influence of water-rock interaction

作　　者：胡惠华 李军伟 范文韬 林滢 贺建清[4] HU Hui-hua;LI Jun-wei;FAN Wen-tao;LIN Ying;HE Jian-qing(Hunan Provincial Communications Planning,Survey&Design Institute Co.Ltd.,Changsha,Hunan 410200,China;Hunan Provincial Key Laboratory of Highway Construction and Maintenance Technology in Southern China,Changsha,Hunan 410008,China;Geological Experiment and Testing Center of Hunan Province,Changsha,Hunan 410007,China;Hunan Provincial Key Laboratory of Geotechnical Engineering for Stability Control and Health Monitoring,Hunan University of Science and Technology,Xiangtan,Hunan 411201,China)

机构地区：[1]湖南省交通规划勘察设计院有限公司,湖南长沙410200 [2]中南公路建设及养护技术湖南省重点实验室,湖南长沙410008 [3]湖南省地质实验测试中心,湖南长沙410007 [4]湖南科技大学岩土工程稳定控制与健康监测省重点实验室,湖南湘潭411201

出　　处：《岩土力学》2025年第3期685-694,共10页Rock and Soil Mechanics

基　　金：国家自然科学基金项目(No.52279100);湖南省自然资源厅科技计划项目(No.湘自资科20230143DZ);湖南省交通运输厅科技进步与创新计划项目(No.202120)。

摘　　要：以沅麻盆地红层软岩为研究对象,开展不同饱水时长下的岩石单轴压缩试验、电镜扫描试验、弹性纵波波速测试,研究饱水红层软岩力学性质、微观结构、弹性纵波波速随时间的变化规律;采用数字图像处理技术对岩石微观结构特征进行量化处理,定量分析岩石微结构变化特征;基于损伤力学理论,构建水化作用下红层软岩损伤模型。研究结果表明,红层软岩饱水1、2、3、5 d后强度分别下降了14%、27%、39%、80%。随着饱水时间的增加,红层软岩单轴抗压强度单调递减,其破坏模式从脆性破坏模式逐渐往延性破坏模式发展,破坏时岩石破裂面与水平面夹角逐渐变小,主贯穿剪切裂缝周围的次生裂纹数量呈先增大后减小的趋势。红层软岩岩样缺陷面积占比随着饱水时间的增长逐渐增加,孔隙数量与孔隙平均尺寸呈负相关,孔隙数量表现为先升高再降低的趋势,红层软岩缺陷面积占比增量与饱水时间呈线性递增关系;同时,随着饱水时间的增长,红层软岩纵波波速降低,expdecl函数适用于拟合红层软岩纵波波速与饱水时间的关系。建立了红层软岩饱水损伤模型,并将模型计算值与试验值进行对比,验证了模型的准确性。该模型能以无损检测的方式准确预测不同饱水时长下岩石的单轴抗压强度,能较好地描述红层软岩饱水后的损伤特性。Focusing on red bed soft rock from the Yuanma Basin,uniaxial compression tests,electron microscope scanning tests,and elastic P-wave velocity tests were conducted to study the changes over time in the mechanical properties,microstructure,and elastic P-wave velocity of the soft rock under different water saturation conditions.Digital image processing technology was used to quantify the characteristics of rock microstructure,and the varying characteristics of rock microstructure were quantitatively analyzed.Based on damage mechanics,a failure model for water-saturated red bed soft rock was established.The results show that the strength of red bed soft rock decreases by 14%,27%,39%,and 80%respectively after 1,2,3,and 5 days of water saturation.As water saturation time increases,the uniaxial compressive strength of red bed soft rock decreases monotonically,and its failure mode gradually transitions from brittle to ductile,with the angle between the rock’s fracture surface and the horizontal plane gradually diminishing.The number of secondary cracks surrounding the main shear fracture initially increases and then decreases.The proportion of defect area in red bed soft rock increases linearly with water saturation time,and the number of pores is negatively correlated with the average pore size,showing a trend of increasing initially and then decreasing.The P-wave velocity of the rock decreases as water saturation time increases,and the expdecl function is suitable for fitting the relationship between P-wave velocity and water saturation time of red bed soft rock.A damage model for water-saturated red bed soft rock was established,and the calculated values from the model were compared with the experimental values,verifying the accuracy of the model.It is concluded that this model can accurately predict the uniaxial compressive strength of rocks after different water saturation times through non-destructive testing and can better describe the damage characteristics of red bed soft rocks after saturation.

关 键 词：红层 软岩 强度 劣化 损伤模型 

分 类 号：TU451[建筑科学—岩土工程]